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Client-Server and Distributed Data Bases - Coggle Diagram
Client-Server and Distributed Data Bases
Motivation
scalability refers to the ability to add and remove capacity in small units.
interoperability refers to the ability of two or more systems to exchange and use software and data.
flexibility refers to the ease of maintaining and adapting a system
Elements
client
program that makes requests to a server
server
performs requests and communicates results to the clients.
site
locally controlled computer with a unique network address
Global requests
queries that combine data from more than one site and transactions that update data at more than one site
Architectures
Three-Tier Architecture
application server for specific kinds of processing
addresses performance limitations of the two-tier architecture
middleware server handle process management.
Multiple-Tier Architecture
provide a finer division of processing
can also improve performance
support additional layers of servers
Two-Tier Architecture
for moderate number of clients
the simplest to implement
for systems with stable requirements
software maintenance can be difficult
Web Services Architecture
generalize multiple-tier architectures for electronic business
interaction
service requestor
service registry
service provider
operate in the Internet
Distributed Database Architecture
useful for organizations operating in multiple locations with local control
local data managers
provide complete features of a DBMS
heterogeneous
homogeneous
distributed data manager
optimizes query execution across sites
coordinates concurrency control
controls access to remote data